Throttle Adjustment

By Gary Fischman

An loose  throttle cable will cause slow response when you mash on the gas pedal. Conversely, a cable that's too tight will not allow the car to drop to proper idle causing excessive fuel consumption. Fortunately, the throttle cable is one of the simplest adjustments under the hood of your Miata.

Start by locating the cable under the hood. It is on the right side of the engine compartment, bolted to the big aluminum intake manifold. The braided cable is the accelerator cable, or throttle cable. There are two nuts holding the cable to the bracket on the manifold. The nut toward the front is a lock nut. The nut at the rear is the deflection adjustment nut.

Loosen the lock nut. Then turn the adjustment nut one way or the other until the deflection in the middle of the cable is between 1 and 3 millimeters. When you have the deflection where you want it, simply tighten the lock nut.

As a precaution another thing to check is for excessive or inadequate cable tension at full throttle. Start by having someone fully but gently press and hold down the gas pedal while you flex the cable to assure that the pulley rotates no further as you do, and that the cable at least flexes a bit with some stout finger pressure. Next have the gas pedal pressed hard down to see that the pulley rotates no more and the same amount of stout cable flexing remains.

Although full throttle cable tension is not usually a problem, it can be if there's been some previous improper setting of the gas pedal stop, or perhaps altered by an accidental collision. The gas pedal stop is located inside the car in the area just above the gas pedal. If improperly set its locking nut should be loosened and the adjustor bolt rotated to reset proper full throttle cable tension. Once set tighten the locking nut and recheck the throttle cable system. The adjusting bolt and its locking nut
have marking paint; so, its easy to see if the adjustment has been altered from its factory setting.

6 September, 2002